package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScorllResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            queryBlogUser(blog);
            isLike(blog);
        });
        return Result.ok(records);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryBlogById(Long id) {
        // 1.查询blog
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("博客不存在");
        }
        // 2.查询blog有关的用户
        queryBlogUser(blog);
        // 3.查询blog的点赞数量
        isLike(blog);
        return Result.ok(blog);
    }

    private void isLike(Blog blog) {
        // 1. 获取登录用户
        Long userId = UserHolder.getUser().getId();
        if (userId == null){
            return;
        }
        // 2. 判断当前登录用户是否已经点赞
        String key = "blog:liked:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    @Override
    public Result likeBlog(Long id) {
        // 1. 获取登录用户
        Long userId = UserHolder.getUser().getId();
        // 2. 判断当前登录用户是否已经点赞
        String key = "blog:liked:" + id;
        Double score= stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if (score != null){
            // 3. 如果已经点赞，取消点赞
            // 3.1 数据库点赞数 + 1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            // 3.2 把用户从Redis的set集合移除
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }

        }else {
            // 4. 如果已经点赞，取消点赞
            // 4.1 数据库点赞数 -1
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            // 4.2 保存用户到Redis的set集合
            if (isSuccess){
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 1.获取用户
        UserDTO user = UserHolder.getUser();
        // 2.查询用户收件箱
        String key = FEED_KEY + user.getId();
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 3.非空判断
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        // 4.解析数据：blogId、minTime、offset
        List<Long> ids = new  ArrayList<>(typedTuples.size());
        long minTime = 0;
        int offsetCount = 1;
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples){
            // 4.1 获取id
            ids.add(Long.valueOf(tuple.getValue()));
            // 4.2 获取分数(时间戳)
            long time = tuple.getScore().longValue();
            if (time == minTime){
                offsetCount++;
            }else {
                minTime = time;
                offsetCount = 1;
            }
        }

        // 5. 根据id查询blog
        String idsStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("order by field(id," + idsStr  + ")").list();
        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryBlogUser(blog);
            // 5.2.查询blog是否被点赞
            isLike(blog);
        }
        // 6.封装并返回
        ScorllResult scorllResult = new ScorllResult();
        scorllResult.setList(blogs);
        scorllResult.setOffset(offsetCount);
        scorllResult.setMinTime(minTime);

        return Result.ok(scorllResult);
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        // 1.查询top5的点赞用户
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 2. 解析出其中的用户id
        List<Long> userIds = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", userIds);
        // 3.根据用户id查询用户
        List<UserDTO> userDTOS = userService.query()
                .in("id", userIds).last("order by field(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user,UserDTO.class))
                .collect(Collectors.toList());
        // 4.返回用户
        return Result.ok(userDTOS);
    }
}
